I have a 2002 Ford Focus. I got stuck tonight trying to replace the driver's side bulb tonight in the cold and dark, so I have not actually done this yet. But after getting home I read this on the Internet:
1. Remove the rubber cover behind the headlamp.
2. Release the bulb from the metal wire/clip that holds it in place. This is where I had trouble and read this advice: The metal wire/clip that holds the bulb in place has to be pushed down, (and perhaps squeezed together?) while pushing it toward the passenger side. This will release it from the catch that holds it in place and free up the bulb.
3. Unplug the plug in the back of the bulb and plug in your new bulb.
4. Reverse the directions to put it back together.
Its hard to get your hands in there, so good luck!
David, December 2007